Calculating device



G. R. FLYNN.

CALCULATING DEVICE.

I APPLICATION man APR.B,1921.

1,426,829 PatentedAug.22,1922.

2 SHEETSSHEET I. 8} I2 F A TTORNE Y.

G. R. FLYNN. CALCULATING DEVICE.

APPLICATION FILED APRB, 1921.

Patented Aug. 22, 1922.

2 SHEETSSHEET 2.

' m ATTORNEY.

UNITED" STATES PATENT/OFFICE.

GEORGE RYAN, FLYNN, OF LOWELL, MASSACHUSETTS.

CALCULATING nnvrcn.

To'all whom it may concern: Be it known-that I, GEonGE R-Y nFLYNN, a citizen of the United States, residing at Lowell, in the county of Middlesex and Stateand compact so that it can be carried in the pocket or in a small circular case.

This device is especially useful for students, but includesvarious scales and formulae useful for surveyors, mechanical engineers, and others who have occasion to figure out mathematical problems.

It is so arranged that most of the calculating devices are of semi-circular form and can therefore be read directly without turning. This is particularly true. of that part of my device which includes a semi-circular slide rule, and I believe that I am the first to devise such a rule.

In the drawings, Fig. 1 is a front view or elevation of my preferred forrn of device, including a semi-circular slide rule, angle formulae, sine tables, and protractor.

- Fig. 2 is an elevation, being a view from theright of Fig; 1.

. Fig. 3 is a view of the top part of the base is it appears without the marks for sine ta- .Fig. 4is an elevation on a smaller size than Fig. 1 of the base with the half disc member and runner removed.

Fig. 5 is a view of a modified form of base in the form of a perfect disc, but with the degrees for the protractor scale omitted, as well as the sine tables, but having the angle formulae and the sliderule scales.

Fig. 6 is an elevation showing a modified form of my device which embodies the semicircular slide rule alone.

In Figs. 4, 5 and 6, the actual markings are in some cases merely indicated, as it is believed this makes for clearness.

In the drawings, A represents a base made of any suitable sheet material in the form.

- Specification of Letters Patent. Patented A 22 1922 Application filed April 8, 1921.

Serial No. 459,617.

12, is a scale showing degrees, and from 12 to 13 a continuation of the same scale showing degrees, the whole being in semi-circular form. Inside the degrees scale, arranged concentrically in semi-circular form, are the scales 8, 9, 14 and 15, showing co-tangents, sines, co-sines, and tangents. These are preferably staggered so that the radial lines 16, 16, running through the scales to the degrees, will not confuse, but willpermit the \Vith pivot point Y as 'a center, half disc member B is revoluble on base A. a The pivot may comprise a headed member 43 and washer 44, which serves as a pivot for B and runner O.

Half disc member B has an inside open slot H of semi-circular form arranged so that the markings 23' will come along one edge, while it is marked at 34 with a slide rule scale. The outer edge of half disc B is cut away to form an outside slot Gr cut ,in such position as to expose the slide rule scale 24, the adjoining curved edge of B being marked with a slide rule scale 35. 26 is the-other marking for a slide rule scale which shows through slot Gr. The part K of half disc member B between the slots H and Pivoted on pivot point Y is a transparent runner C. which extends out over'the edge of B and A, as shown at 41 and 42 in Fig, 2. This is marked with a hair line 40 which crosses the slide rule scales and is used to assist in readin them.

As shown in *ig. 3, the upper part 10 of the base A may be simply marked with the degrees, leaving out the sine tables, the rest of the device being the same as shown in Figs. 1 and 4. In thiscase. the combination consists of the slide rule, angle formulae and protractor.

As shown in Fig. 5, the base P may be a.

perfect disc, with its upper half without degrees scale or sine table markings, but having the slide rule markings 23, 24, 26 and the angle formulae markings 19, 21, 22. This forms the combination of the semi-circular slide rule and the angle formulae.

As shown in Fig. 6, base R may be a rfect disc with its upper part free from markings of any kind, but with its lower half having the slide rule markings 23, 24, 26, and the half disc member S pivoted at the pivot point Y having; the inside slot H, outside slot Gr and the semi-circular slide part K between them, having the slide rule markings 34: and 35. This arrangement forms a semi-circular slide rule alone.

I claim:

1. In a calculating device, the combinationof a base having a straight-edged slot with a straight edge which coincides with the diameter line for a series of scales arranged concentrically in semi-circular form, the outside scales showing degreesand the inside scales showing the corresponding sines, co-sines, tangents and co-tangents, and a pivot point on a second center, together with scales arranged in semi-circular form with said pivot point as a center showing the markings of one member of a slide rule and other markings arranged in a semi-circular form with reference to said pivot point showing angle formulae, with a half disc member revoluble on said pivot so cut as to expose the slide rule markings of the base so as to form a semi-circular slide member of the slide rule with markings thereon and having apertures in proper relation to read the angle formulae, together with a transparent runner pivoted on said pivot and having a hair line which crosses the slide rule scales.

2. In a calculating device, the combination of a base having a slot with a straight edge in which is the center point of a semicircular scale and a pivot point which is at another center for semi-circular slide rule scales and a curved angle formula scale marked'on said base, with a half disc member pivotal on said pivot oint so cut as to form a semi-circular sli e member with scales thereon for the slide rule and with apertures to disclose the angle formula scale, together with a trans arent runner pivotal on said pivot point aving a hair line which crosses the slide rule scales.

3. In a calculating device, the combination of a base having, aslot with a straight edge in which is the center point of a semicircular scale, and a pivot point which is at another center for semi-circular slide rule scales and another scale marked on said base, with a half disc member pivotal on said pivot point so cut as to form a semicircular slide member with scales thereon for the slide rule and with apertures to disclose the other scale, together with a transparent runner pivotal on said pivot point having a hair line which crosses the, slide rule scales.

4. Ina calculating device, the combination of a base'having a pivot point for a semi-circular slide rule scale and another scale, with a half disc member pivotal on said pivot point so cut as to form a semi- 'circular slide member with scales thereon for the slide rule and with apertures to disclose the other scale, together with a transparent runner pivotal on said pivot point having a hair line which crosses the slide rule scales.

5. In a calculating device, the combination of a base having sem1-circular slide rule scales and a pivot point therefor, with a half disc member with slide rule scales, pivotal on said pivot point so cut as to form a semi-circular slide member for the slide rule and a transparent runner pivotal on GEORGE RYAN FLYNN. 

